\input pstfig
\hskip 2cm
$
\setcoorunit{4}{1}
\psset{yunit=0.3\psxunit}
\psset{xunit=1.2\psxunit}
\drawaxes{-2.1}{2.5}{-5.7}{6}
\markxlabel{-1.5}{-\frac{3}{2}\pi}{-2.1em}
\markxlabel{-0.5}{-\frac{\pi}{2}}{-1.5em}
\uput[-50](0,0){\scriptstyle O}
\markxlabel{0.5}{\frac{\pi}{2}}{1em}
\markxlabel{1.5}{\frac{3}{2}\pi}{1.5em}
\psplot{-0.44}{0.44}{tan(x*\pinum)}
\psplot{-1.44}{-0.56}{tan(x*\pinum)}
\psplot{0.56}{1.44}{tan(x*\pinum)}
\dashline\thinline
\psline(-1.5,5.3)(-1.5,-5.3)
\psline(-0.5,5.3)(-0.5,-5.3)
\psline( 0.5,5.3)( 0.5,-5.3)
\psline( 1.5,5.3)( 1.5,-5.3)
$
\bye
